/Engine/Plugins/FX/Niagara/Source/Niagara/Public/NiagaraRenderableMeshInterface.h
Get used materials.
void GetUsedMaterials ( [FNiagaraSystemInstanceID](API\Plugins\NiagaraCore\FNiagaraSystemInstanceID) SystemInstanceID, [TArray](API\Runtime\Core\Containers\TArray)< [UMaterialInterface](API\Runtime\Engine\Materials\UMaterialInterface) * > & OutMaterials ) const